Preparation of light stable hops

ABSTRACT

Disclosed are methods for the production of light stable hops, useful for the brewing of beer or ale to be stored in clear or green glass containers, which beer or ale will not develop objectionable flavor as a result of exposure to light. Light stable hops are prepared by double extraction of liquid/supercritical CO 2  extracted hop solids with ethanol to remove alpha/iso-alpha-acids. Such alpha/iso-alpha-acids may be further removed from the ethanol extraction liquor obtained in the double extraction process by subjecting such liquor to an ion exchange medium, or precipitation by a metal ion, heavy metal ion, or alkali metal ion, to provide an alpha/iso-alpha-acids free extraction liquor which may be added to the light stable hops residue obtained in the initial double extraction process.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 10/106,603filed Mar. 26, 2002.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the invention

This invention relates to the treatment of hop solids which is theresidue remaining after liquid or supercritical CO₂ extraction, andproduces a hop product which imparts not only hop flavor and mouthfeelindistinguishable from original whole hops, but also provides lightstability and flavor variations in malt beverages. Such treated hopsolids can contribute hop flavor and mouthfeel to beer with lowbitterness. However, a residual amount of alpha/iso-alpha-acids, whichcauses light instability in finished malt beverages, is still present inthe hop solids. The present invention is directed to the preparation oflight stable hop products, containing little or no alpha/iso-alpha-acid,for providing hop flavor and character for beer products which may bepackaged in flint, clear, or green bottles.

2. Description of the Related Art

Hops, in the form of either the ground dried plant or pellets, are usedin brewing to give malt beverages such as beer or ale their essentialcharacteristics of aroma, flavor, mouthfeel, and bitterness, as well ascontributing foam and anti-microbial activity to the brew. The hops areusually added to the boiling wort in the brewing kettle, and thenfermented by yeast to produce the finished product. During boiling,alpha-acids in the hops are converted into iso-alpha-acids, whichcontribute the bitterness and foam in the finished product. Suchiso-alpha-acids are, however, susceptible to a photochemical reactionwhich produces “skunk”, an undesirable sulfur flavor characteristicresulting from the presence of 3-methyl-2-butene-1-thiol. This reactionis known to occur when the finished product is packaged in flint orgreen bottles and exposed to light.

Hops may be separated into hop soft resins, i.e. CO₂ hop extract(containing the extracted alpha-acids, beta-acids, and hop oil fractionor HOF), and hop solids, by employing liquid/supercritical CO₂ orless-polar organic solvent extractions. The CO₂ hop extract contributesmost of the bitterness flavor in beer. Beer brewed solely with the CO₂hop extract does not impart a complete hops flavor spectrum to the beerdue to the absence of the water-soluble components, which apparentlyremain in the hop solids. The bitterness flavor can also be added aspure forms after fermentation or in the finished products. To integratethe full spectrum of hop flavor would thus require the addition of hopsolids to the brew, but the hop solids have been found to contain traceamounts of alpha/iso-alpha-acids, which, due to lack of light stability,contribute to skunkiness in beer. Therefore, to obtain the full flavorof the hops while avoiding skunkiness in beer, light stable hops wouldbe of value.

It is known that there are a number of U.S. patents relative to thismatter, such as Ting et al. U.S. Pat. No. 5,783,235, which teaches thepreparation of a hop flavored, less bitter fermented beverage byaddition of the solid hop residue remaining after CO₂ extraction (as thesole hopping agent) to the wort, boiling the mixture, removing thesolids from the fermented mixture, and fermenting the remainder toobtain the final product. While this method does provide a brew havingless bitterness but a comparable hop flavor to a brew prepared usingwhole hops, it does not fully address the issue of iso-alpha-acidspresent in the solid hop residue. In a preferred embodiment of the Tinget al. '235 method, the solid hop residue and the hop oil fraction(HOF), which is the residue of a hop extract remaining after removal ofalpha-acids and beta-acids from the hop extract obtained from the CO₂extraction, are pelletized and added to the wort prior to or duringboiling. After the mixture is boiled and fermented with yeast to convertthe hop components and the wort, the solids are then separated to obtainthe liquid product. Since the solid hop residue is present in thebrewing kettle, iso-alpha-acids are present in the final brew,potentially leading to an undesirable skunk flavor.

Ting et al., in U.S. Pat. No. 5,767,319, teach conversion ofiso-alpha-acids to light stable tetrahydroiso-alpha-acids, which areknown bittering agents. While an improvement over previous conversionmethods, the patent necessitates additional treatment steps to obtainspecified metal salts of the iso-alpha-acids, dissolving the metal saltsin an aqueous alcohol medium, and reducing the iso-alpha-acids byhydrogenation under specific conditions to form thetetrahydroiso-alpha-acids, which are then recovered from the reactionmedium. Such a method clearly adds complexity to the desired goal ofproviding a light stable form of hops.

In addition, Ting et al. teach, in U.S. Pat. No. 6,020,019, a method forthe hydrogenation of hop soft resins, wherein carbon dioxide is used asa reaction solvent, in liquid or supercritical fluid form, for theconversion of iso-alpha-acids or beta-acids to tetrahydroiso-alpha-acids(tetrahydroisohumulones), preferably using an acidic lower alcohol toact as a promoter for the beta-acids. As previously indicated,tetrahydroiso-alpha-acids are known light-stable FDA-approved bitteringagents which may be used to add hop flavoring to beer. In this patent,it was noted that the tetrahydroiso-alpha-acids were previouslygenerally not made from the alpha-acids for economical reasons. Thehydrogenation method of this patent permits the use of alpha-acids as asource of tetrahydroiso-alpha-acid for use in brewing.

Additional patents to Ting et al. include U.S. Pat. Nos. 5,523,489,5,874,633, and 5,917,093. In these patents, methods for the preparationand/or purification of tetrahydroiso-alpha-acids(tetrahydroisohumulones) are discussed. In U.S. Pat. No. 5,523,489,tetrahydroisohumulones are prepared from isohumulones by hydrogenationin ethanol. In U.S. Pat. No. 5,917,093, alpha-acids and beta-acidspresent in the hop oil fraction of CO₂ Hop Extracts are purified bymixing with an absorbent to remove catalyst poisons, thereby reducingthe amount of catalyst necessary for hydrogenation totetrahydroiso-alpha-acids and tetrahydrodesoxy-alpha-acids. In U.S. Pat.No. 5,874,633, patentees teach a method of hydrogenating and formulatinga starting solution of iso-alpha-acids to obtain concentrated solutionsof tetrahydroiso-alpha-acids.

In U.S. Pat. No. 5,972,411, Goldstein et al. teach the isolation andcharacterization of a group of odorless and non-volatile glycosides fromextracted hops (hop solids which have previously been extracted withliquid/supercritical CO₂ or less-polar solvents.) These glycosides arewater soluble and consist of a group of aromatic compounds conjugated tomono-, di- and tri-saccharides. These glycosides are responsible for theformation of kettle hop flavor. Through both chemical and biologicaltransformations, an essence and flavorant can be prepared for additionto an unhopped beer. These kettle hop flavor essences and flavorantsprovide economy, consistency, flexibility, quality and convenience tothe brewing process because only one unhopped wort is required to brew astock of unhopped beer, which can then be dosed with the desired amountof kettle hop flavor essence and flavorant.

In U.S. Pat. Nos. 5,013,571 and 5,013,572, Hay teaches methods forconverting alpha acids to hop bittering flavors by exposing the alphaacids to an environment capable of isomerizing and reducing the alphaacids to form either tetrahydroiso-alpha-acids or hexahydroiso-alphaacids, and then steam stripping odor forming impurities from such toproduce purified light stable hop bittering compounds.

In addition to the above, U.S. Pat. No. 4,002,683, of Todd, Jr., teachesa process for isomerizing alpha acids to iso-alpha-acids by contact withan aqueous solution of a metal ion to form materials suitable for use asbittering additives, wherein a water-immiscible organic solvent in whichthe alpha acid is soluble is employed. Todd, Jr., also teaches, in U.S.Pat. No. 4,666,731, the separation of the constituents of CO₂ HopExtracts employing aqueous alkali, followed by conversion of theseparated alpha acid fraction into an iso-alpha acid or isohumulonefraction useful in the bittering of beer. Moreover, Todd, Jr. et al.teach, in U.S. Pat. Nos. 4,778,691 and 4,956,195, the removal ofodor-forming impurities from hop flavors by extracting into water at apH above 5, and separating the aqueous phase containing the impuritiesfrom the purified hop flavors, to recover a flavoring agent selectedfrom unreduced and reduced alpha acids and iso-alpha-acids which isessentially odor-causing-impurity free. And, in U.S. Pat. No. 5,073,396,Todd, Jr. teaches the use of a non-acidic hop flavor fraction forproduction of beer, wherein the hop flavor fraction is made from CO₂ hopextract to provide an extract essentially devoid of alpha and betaacids, by fractionation of the hop extract with an alkaline solutionwithin controlled pH ranges. In U.S. Pat. No. 5,296,637, Stegink et al.teach production of odor-free tetrahydroisohumulates from alpha acidsvia the tetrahydrohumulates and subsequent isomerization.

Thus, there are a number of processes for the preparation, separation,purification, and use of hop bittering flavors for beer. However, amethod for the production of light stable hops containing little or noalpha/iso-alpha-acids, which also imparts hop aroma and flavor to thebrewing of beer equivalent to or comparable to the aroma and flavorattained from the use of conventional hops, has not previously beenprovided.

SUMMARY OF THE INVENTION

The present invention provides means for providing light stable hopswhich impart hop aroma and flavor to beer, without the potential forlight sensitivity resulting in skunkiness. Several techniques have beenemployed to prepare light stable hops, which were evaluated by sensorytesting for light stability and acceptable hop flavor attributes. Thesetechniques included exhaustive extraction (double extraction, or DX) ofhop solids to obtain a basic hop residue and an extract containing mostof any trace alpha/iso-alpha-acids; applying an ion exchange removal ofthe alpha/iso-alpha-acids in the extract from said double extraction,followed by return of the effluent from said ion exchange to the residueof the double extraction, and concentration of this mixture to obtain amore flavorful light stable hop; and utilizing a metal ion precipitationtreatment removal of alpha/iso-alpha-acids in the extract from saiddouble extraction, followed by return of the filtrate of saidprecipitation treatment to the residue of the double extraction, andconcentration of this mixture to obtain a light stable hop.

When the products of these techniques were used in the preparation ofbrewed beer, the resulting brews were confirmed to be light stable, andthe light stable hops employed made a contribution to kettle hop flavorattributes. Still further, it was found that a full form of hop wasreconstituted with a hop oil fraction (HOF), a beta-acid rich fraction(which is obtained from the hop extract resulting from initialpreparation of the hop solids by liquid or supercritical CO₂extraction), and light stable bittering agents (and prior to the doubleextraction method of the present invention) to each of these lightstable hops and yielded a further flavor improvement without causinglight instability in brewed product.

It is thus an advantage of the present invention to provide aninexpensive method for the preparation of light stable hops, which areuseful in providing hop flavor and mouthfeel for brewed product to bepackaged in clear, flint or green bottles. Such brewed product is foundto be less subject to skunk flavor resulting from exposure to light overtime.

DETAILED DESCRIPTION OF THE INVENTION

Methods for Preparation of Light Stable Hops

A thermal decomposition of hop solids in the presence of hot air wasunsuccessful, and most residual amounts of alpha-acids were convertedinto iso-alpha-acids, resulting in a light unstable product. Directisomerization and reduction of trace amounts of alpha-acids to lightstable rho-iso-alpha-acids (or dihydro iso-alpha-acids) in an aqueoushop solid slurry was attempted, employing a caustic sodium borohydridesolution (NaBH₄). Results were inconsistent, and high performance liquidchromatography (HPLC) analysis indicated that the reduction inalpha-acid content was ineffective due to interference of hop solidmaterials.

Since it is known that trace amounts of alpha/iso-alpha-acids (about0.1-0.5 weight percent) seem to bind very tightly within the hopcellulose matrix, thus making a direct chemical reaction or reductiondifficult, it was decided to attempt the reduction or elimination ofalpha/iso-alpha-acids by extraction in a homogenous solution system. Lowmolecular weight alcohols, such as methanol or ethanol, are capable,with efficient mixing, of extracting sufficient amounts ofalpha/iso-alpha-acids from hop solids. Due to the cost and potentialtoxicity of methanol, ethanol has been utilized. In addition to beingsafe for consumption, 95% ethanol is less soluble for the water-solublecompounds and very soluble for the alpha/iso-alpha-acids. An analyticalscale extraction condition was established by comparing the extractionefficiency of acidic 95% ethanol, 95% ethanol, acidic 70% ethanol, and70% ethanol, using Galena hop solids.

The Hop Solids Double Extraction Technique

To 200 grams of ground hop solids (prepared from either Cascade hops orGalena hops) was added 600 ml of 95% ethanol. The mixture was thenagitated, with a magnetic stir bar, for one hour, followed by vacuumfiltration through a Whatman #4 filter paper. The filtrate was retained.The extraction was repeated with another 600 ml of 95% ethanol, and themixture was again vacuum filtered through a Whatman #4 filter paper. Theresidues on the funnel were washed with an additional 100 ml of 95%ethanol. Both filtrates from the two extractions were combined, and theresidues were collected. Results are shown in Table 1. TABLE 1Extraction Efficiency Analyzed by HPLC Extraction Density (g/ml) ofalpha/Iso-alpha-acid in Galena Solution Extract Hop Solids (%) 95%ethanol, Acid 0.81 0.12 95% ethanol 0.99 0.10 70% ethanol, Acid 1.040.15 70% ethanol 1.02 0.12

Although the acidic ethanol solutions are demonstrably more effectivethan neutral solutions, it is possible that the acid may damage theflavor elements of hop solids, or interfere with subsequent treatments.It is also noted that higher water composition solvents co-extract morewater soluble compounds. For instance, a dark green color solution (withdensity of 0.99 g/ml) was obtained using 95% ethanol, while ayellow-brownish color solution (with a density of 1.02 g/ml) wasobtained using 70% ethanol. In other words, a total mass of greater than25% by weight was obtained as compared to 6% when the water compositionwas increased to 30% (70% ethanol/water) from 5% (95% ethanol)extraction of hop solids. The best results for the reduction andminimization of alpha/iso-alpha-acids appeared to occur in a lesscomplicated 95% ethanol extract. Therefore, hop solids were extractedusing 95% ethanol until most of the alpha/iso-alpha-acids were removed,and subjected to the subsequent treatments. This usually required twoconsecutive extractions, and the hop solid residues after such a doubleextraction using 95% ethanol still retain most of the potentialwater-soluble flavor precursors. This double extracted hop solid residuewas then adopted as a basic light stable hop, and further treatment ofthe liquid filtrate from the double extraction to recover minor amountsof flavor precursors was considered.

Further Treatment of the Double Extracted Hop Solids Filtrate

The treatment sought should selectively minimize alpha/iso-alpha-acids,but should also be mild and inert to the flavor precursors.Hydrogenation, sodium borohydride reduction, caustic treatment, ionexchange, alkali metal and metal precipitation were considered for theelimination of alpha/iso-alpha-acids, or for conversion ofalpha/iso-alpha-acids into light stable forms. Hydrogenation wasunsuccessful. Sodium borohydride reduction of iso-alpha-acids torho-iso-alpha-acids was possible, but the subsequent removal ofundesirable boron compounds added extra steps and expense, and wastherefore considered inefficient. However, both ion exchange and alkalimetal or metal ion precipitation showed promising results. The thustreated aqueous ethanol solutions were recombined with the residues andthe aqueous ethanol in the mixture was then removed via evaporation toform reconstructed light stable hops. The two successful methods aredemonstrated hereinafter.

Ion-Exchange Treatment

A basic ion exchange resin has been used in the past to separatealpha/iso-alpha-acids from methanolic, ethanolic, and hexane extract ofhops. Such methods have been used to chromatographically purifyalpha-acids, beta-acids, and iso-alpha-acids from hops or hop extract,in which various organic solvents and buffering solutions were used. Wealtered this methodology to retain the alpha/iso-alpha-acids on theresins by varying the affinity of the effluent and allowed an elution ofalpha/iso-alpha-acids-free effluent. Recombining thealpha/iso-alpha-acids-free effluent and the extracted hop solid residuesafforded a slurry. Evaporation of the aqueous ethanol and drying of theslurry afforded a less distinguishable hop product than the original hopsolids, but containing no light unstable alpha/iso-alpha-acids. Twotypes of ion exchange resins, BIO-RAD AG 1X4 and 3X4, available fromBio-Rad Laboratories of Richmond, Calif. were used. Due to pKadifferences, the dissociated alpha/iso-alpha-acid ions exchange withthese anions (Cl⁻, OH⁻, and acetate ion) on the resins. The ethanolextracted solution of the hop solids was diluted with water (eitherneutral or pH 8) to increase affinity between alpha/iso-alpha-acids andresins. Ion exchange may be performed on either a column or batch basis.For convenience, a batch basis was used in our experimentation. As aresult, the residual alpha/iso-alpha-acids were significantly reduced,as shown in Table 2, items 3, 4, 5, 6, 11, and 12.

Ion Exchange Technique

Two BIO-RAD anion exchange resins (AG 1-X4, and 3-X4, 400 mesh, chlorideform) were pre-rinsed with distilled water. The filtrate was dilutedwith a 1:1 ratio of either distilled water or a pH 8 buffer solution,and then added to the ion exchange resins at an amount of 5% of thetotal mixture. The mixture was allowed to mix for one hour, thenfiltered through a Whatman #4 filter paper. The filtrate was mixed withthe double extracted residues. The hop residues and the extracted flavorprecursors present in the filtrate were simultaneously and homogeneouslymixed while the aqueous ethanol was evaporated off by a vacuum rotaryevaporator. The resultant hop solids were then dried for final usage.

Alkali Metal or Metal Ion Precipitation

Hop alpha-acids and iso-alpha-acids often show a characteristic ofcomplexing with alkali metal ions, divalent ions, and transitional metalions such as magnesium, calcium, lead, ferric, zinc, etc. The tri-ketogroup on the molecule has the functionality of chelating with variousmetal ions. Some of the complexes thus formed are less soluble in waterand alcohol. Accordingly, in order to select desirable and effectivealkali metal or metal ions which comply with FDA regulations, and tostill meet brewing requirements, a number of inorganic salts such ascalcium carbonate, calcium hydroxide, magnesium hydroxide, magnesiumacetate, zinc sulfate, and zinc acetate were selected.

Alkali Metal/Metal Ion Precipitation Technique

To 1200 ml. of filtrate from the double extraction, an equal amount ofdistilled water was added to reduce the solubility of subsequent formingcomplexes of alpha/iso-alpha-acids. From 1 to 5 grams of the alkalimetal or metal salts, Ca(OH)₂, Ca(OAc)₂, CuCl, CuS0₄, ZnSO₄, andZn(OAc)₂, respectively, were added to the diluted filtrate, and mixedfor one hour at room temperature. The amounts of alpha/iso-alpha-acidwere monitored by HPLC, until no further reduction was observed. Theprecipitate was removed by filtration through a Whatman #4 filter paper,and the filtrate was then added back to the solid residues of the doubleextraction in a 5 liter round bottom flask. The thus formed mixture wasrotary evaporated (under 31 torr at 40-50° C.) to remove ethanol andwater. Lyophilizing removed the residual moisture and afforded driedsolids for subsequent usage. A number of light stable hops were thusprepared and analyzed by HPLC (as shown in Table 2). TABLE 2 Data ofLight Stable Hops Added in Brews Addition Rate % Residual alpha/ #LS-Hops Type Treatment (ppm) Iso-alpha-acids 1 Galena Hop None 20000.110 Solids 2 Cascade Hop None 2000 0.080 Solids 3 1A - Galena 1 × 4 -pH 8 1592 0.010 4 1B - Cascade 1 × 4 - pH 8 1434 0.014 5 3A - Galena 1 ×4 - neutral 1630 0.040 6 3B - Cascade 1 × 4 - neutral 984 0.003 7 4A -Galena - CuSO₄ 1612 0.037 8 4B - Cascade CuSO₄ 1288 0.014 9 5A - GalenaCu(OAc)₂ 862 0.019 10 5B - Cascade Cu(OAc)₂ 660 0.010 11 6A - Galena 3 ×4 - neutral 1216 0.015 12 6B - Cascade 3 × 4 - neutral 1338 0.036 137A - Galena Ca(OH)₂ 846 0.012 14 7B - Cascade Ca(OAc)₂ 1468 0.017 158A - Galena CuCl 1570 0.042 16 8B - Cascade CuCl 1194 0.010 17 9A -Galena ZnSO₄ 860 0.013 18 9B - Cascade ZnSO4 1476 0.021 19 10A - GalenaZn(OAc)₂ 1288 0.023 20 10B - Cascade Zn(OAc)₂ 1760 0.029 21 11A - GalenaNaBH₄ 1538 0.110 22 11B - Cascade NaBH₄ 1846 0.085 23 12A - GalenaDouble X 1920 0.048 24 12B - Cascade Double X 1748 0.016 25 13A - GalenaDouble X + HOF 192 0.048 26 13B - Cascade Double X + HOF 175 0.016Pilot Brews Hopped With Candidate Light Stable Hops

Despite the estimation and prediction of light stability, actual lightstability must be confirmed by sensory observation. Possible lightstable hops made in accordance with each of the four techniquesdiscussed above, and other treated light stable hop samples, weresubmitted for pilot brews, as follows.

The double extracted residues (Double X, Examples 23 and 24) employing95% ethanol extraction, were brewed at 1920 and 1748 ppm, respectively,as Pilot Brews 8679 and 8670.

To evaluate the effect of the Hop Oil Fraction (HOF) and compensate forthe loss of aroma and flavor components resulting from doubleextraction, 1 gram of HOF was added to 8 grams of the double extractedresidues (Examples 25 and 26). These were brewed at 192 and 175 ppmlevels, as Pilot Brews 8685 and 8686.

Ion exchange resin treated samples (Examples 3, 4, 5, 6 and 11) werebrewed as Pilot Brews 8664, 8666, 8665, 8667, and 8673. Sample 12 didnot brew due to containing a higher alpha/iso-alpha-acids content.

Additional Pilot Brews, numbered 8671, 8672, 8674, 8675, 8676, 8677,8683, 8681, and 8682 were hopped with various alkali metal ionprecipitated light stable (LS) Hops corresponding to Examples8,10,13,15, 16, 20, 14, 18, and 19, respectively.

In addition to the above, two sodium borohydride reduction treated hopsolids (Examples 21 and 22) were brewed as Pilot Brews 8678 and 8684.Three control Pilot Brews, Numbers 8661, 8662, and 8663, were unhopped(8661) and hopped with 2000 ppm of Galena hop solids (8662) and Cascadehop solids (8663), respectively. Analytical data may be found in Tables3 and 4, hereinafter.

Sensory Evaluation of Pilot Brews: Light Stability

Samples of the Pilot Brews, all bottled in 12 oz clear bottles, thenpackaged in six-pack paper carriers having a height of 5¼ inches, wereexposed to 25 foot-candles of fluorescent light for 20 days. A total of23 products were thus evaluated. Testing was conducted on each exposedsample, and compared to a corresponding unexposed sample. All suchtesting involved subjectively rating the samples on sulfur character andskunky character. Mean scores are based upon a 24-point linear scale,where 1 is weak, and 24 is strong. The results are set forth in Table 4.

Sensory Evaluation of Pilot Brews: Round Table Evaluation

Pilot brews were prepared and characterized in round table sensoryevaluation, based upon promising results in light stability testing. Thepurpose of such testing was to obtain a descriptive profile of eachunexposed LS-Hops candidate. The Cascade based LS-Hops candidates seemedto have stronger, fruity/estery notes than the Galena LS-Hopscandidates. Panelists also indicated preferences for pilot brews 8680,8686, 8676, 8683, 8667, 8672, and 8673. Of these, only the last wasbased upon a Galena hop solids. These evaluations are shown in Table 4.

Correlation between Sensory Light Stability and Analyticaliso-alpha-acids

A general good correlation between sensory scores (skunkiness) andanalytical iso-alpha-acid content demonstrated that the limitediso-alpha-acids present in the Pilot Brews prepared from lowiso-alpha-acid content LS-Hops were less subject to skunkiness, and weremore acceptable. Analysis indicated that light stable hops preferablyhave iso-alpha-acid contents of less than 0.2-0.3 ppm. TABLE 3 Summaryof Light Stability and Skunkiness Brew Iso-α-acids Stability SensoryScore # LS-HOPS # % (ppm) Prediction Exposed/None Skunkiness 0 Unhopped8661 None Yes 3.4/2.9 none 1 Galena Hop Solids 8662  0.11 (2.20) No17.0/2.9  very strong 2 Cascade Hop Solids 8663 0.080 (1.60) No14.5/2.9  very strong 3 1A - 1 × 4 pH 8 8664 0.010 (0.02) Yes 10/3/3.0strong 4 1B - 1 × 4 pH 8 8666 0.014 (0.20) Yes 4.9/3.0 trace 5 3A - 1 ×4 neutral 8665 0.046 (0.65) Marginal 15.8/2.9  very strong 6 3B - 1 × 4neutral 8667 0.003 (0.03) Yes 4.8/3/1 trace 7 4A - CuSO₄ 0.037 (0.60)Marginal 8 4B - CuSO₄ 8671 0.014 (0.18) Yes — Discarded 9 5A - Cu(OAc)₂0.019 (0.16) Marginal 10 5B - Cu(OAc)₂ 8672 0.010 (0.07) Yes 2.9/2.6none 11 6A - 3 × 4 neutral 8673 0.015 (0.18) Yes 4.4/2.5 trace 12 6B - 3× 4 neutral 0.036 (0.48) No 13 7A - Ca(OH)₂ 8674 0.012 (0.10) Yes3.8/2.6 none 14 7B - Ca(OH)₂ 8683 0.017 (0.25) Yes 4.0/3.7 none 15 8A -CuCl 8675 0.042 (0.66) No 4.1/3.2 none 16 8B - CuCl 8676 0.010 (0.12)Yes 2.7/3.0 none 17 9A - ZnSO₄ 0.013 (0.11) Yes 18 9B - ZnSO₄ 8681 0.021(0.31) Yes 4.3/3.2 trace 19 10A - Zn(OAc)₂ 8682 0.023 (0.30) Marginal2.9/2.7 none 20 10B - Zn(OAc)₂ 8677 0.029 (0.51) Marginal 6.7/2.7 slight21 11A - SWS 8678 0.110 (1.69) No 8.9/2.6 moderate 22 11B - SWS 86840.085 (1.57) No 10.3/2.8  strong 23 12A - DX 8679 0.017 (0.32) No6.1/2.6 slight 24 12B - DX 8680 0.016 (0.28) Yes 2.7/2.3 none 25 13A -DX + HCF 8685 0.048 (0.09) Yes 3.6/2.8 trace 26 13B - DX + HCF 86860.016 (0.03) Yes 3.0/2.7 none

TABLE 4 Sensory Round Table Evaluation LS-Hops P.B. Round TableEvaluation #4 - 8666 Slight fruity/estery; low aroma strength; low to 1× 4 pH 8 moderate Sulfur; slight hop aroma; slightly malty; water/thin#6 - 8667 Low to moderate fruity; hoppy aroma; hoppy taste 1 × 4 neutral#10 - 8672 Fruity/estery/banana; slight hop aroma; thin slight Cu(OA)₂lingering after taste; slight metallic; slight sulfur #11 - 8673 Slightfruity; slight hoppy aroma; hoppy flavor; 3 × 4 neutral slight lingeringaftertaste; malty #13 - 8674 Low aroma and fruity; low to moderate hoparoma; Ca(OH)₂ slight hoppy taste; slight malty #14 - 8683Fruity/estery; hoppy taste; hoppy aroma; slight citrus Ca(OAc)₂ aroma;slight lingering aftertaste; slight mouthcoat #15 - 8675 Slight fruity;hoppy aroma; slight malty; lingering CuCl aftertaste #16 - 8676 Low tomoderate fruity; hoppy aroma; hoppy taste; CuCl slight metallic; slightastringent #18 - 8681 Low to moderate fruity/estery; hoppy aroma; clove;ZnSO₄ solvent aroma; slight astringent #19 - 8682 Low to moderatefruity; clove solvent aroma; malty; Zn(OAc)₂ hoppy taste; sulfur #23 -8679 Slight fruity; low malt; harsh; lingering aftertaste DX #24 - 8680Low to moderate fruity/estery; low to moderate hop DX aroma; moderatehop flavor; sulfur; low aftertaste #25 - 8685 Hoppy aroma; hoppy taste;lingering bitter aftertaste DX + HOF #26 - 8686 Fruity/estery; low aromastrength; fruity, floral, DX + HOF citrus taste; slight lingeringaftertaste

Although the present invention has been described in considerable detailwith reference to certain preferred embodiments, one skilled in the artwill appreciate that the present invention can be practiced by otherthan the preferred embodiments, which have been presented for purposesof illustration and not of limitation. For example, alternative forms ofhop solids, other than the Galena and Cascade hop solids utilizedherein, may be used.

Therefore, the scope of the appended claims should not be limited to thedescription of the preferred embodiments contained herein.

INDUSTRIAL APPLICABILITY

The methods taught herein are useful in the preparation of brewedbeverages, such as beer and ale, and specifically permit the brewing ofbeers and ale which may be stored in uncolored or non-light filteringcontainers with little or no danger of development of objectionableskunkiness.

1. A method for the preparation of a light stable hop product, themethod comprising: mixing hop solids with a first alcohol solvent toform a mixture of the hop solids and the first alcohol solvent, the hopsolids being residue obtained by extracting hops with carbon dioxide;separating the mixture of the hop solids and the first alcohol solventinto treated hop solids and a first filtrate including alpha/iso-alphaacids; mixing the treated hop solids with a second alcohol solvent toform a mixture of the treated hop solids and the second alcohol solvent;and separating the mixture of the treated hop solids and the secondalcohol solvent into hop solids residues and a second filtrate includingalpha/iso-alpha acids, wherein a light stable hop product comprising thehop solids residues containing no alpha/iso-alpha acids is formed. 2.The method of claim 1, wherein the first alcohol solvent and the secondalcohol solvent are aqueous ethanol having a concentration of from 10 to95 percent ethanol.
 3. The method of claim 1, further comprising:blending the hop solids residues with a hop oil fraction to form thelight stable hop product.
 4. The method of claim 1, further comprising:blending the hop solids residues with a beta-acid rich fraction to formthe light stable hop product.
 5. The method of claim 1, furthercomprising: blending the hop solids residues with light stable bitteringagents to form the light stable hop product.
 6. The method of claim 1,further comprising: blending the hop solids residues with a member ofthe group consisting of a hop oil fraction, a beta-acid rich fraction, alight stable bittering agent, and mixtures thereof to form the lightstable hop product.
 7. The method of claim 1 further comprising:contacting said first filtrate or said second filtrate with an ionexchange resin to remove alpha/iso-alpha-acids; and blending an effluentof said ion exchange with the light stable hop product.
 8. The method ofclaim 7 further comprising: evaporating off aqueous alcohol from thelight stable hop product.
 9. The method of claim 7, wherein said ionexchange resin is in its chloride, hydroxide, or acetate ion form. 10.The method of claim 7 wherein said light stable hop product is furtherblended with hop oil fraction.
 11. The method of claim 7 wherein saidlight stable hop product is further blended with beta-acid richfraction.
 12. The method of claim 7 wherein said light stable hopproduct is further blended with light stable bittering agents.
 13. Themethod of claim 7 wherein said light stable hop product is furtherblended with a member of the group consisting of hop oil fraction, abeta-acid rich fraction, a light stable bittering agent, and mixturesthereof.
 14. A method for the preparation of a light stable hop product,the method comprising: mixing hop solids with a first alcohol solvent toform a mixture of the hop solids and the first alcohol solvent, the hopsolids being residue obtained by extracting hops with carbon dioxide;separating the mixture of the hop solids and the first alcohol solventinto treated hop solids and a first filtrate including alpha/iso-alphaacids; mixing the treated hop solids with a second alcohol solvent toform a mixture of the treated hop solids and the second alcohol solvent;and separating the mixture of the treated hop solids and the secondalcohol solvent into hop solids residues and a second filtrate includingalpha/iso-alpha acids, wherein a light stable hop product comprising thehop solids residues is formed, and wherein the method further comprisesbrewing a beverage with the light stable hop product.